It seems as though a combination of substrate and coating can require additional drying time before accurate measurements can be done in strip mode. This user found that it took 3 days for full drying before he was able to do the measurement successfully.

This is likely due to the differences between a water-based coating and a solvent-based coating. Solvents will evaporate more quickly and completely, but with obvious odor and potential health issues, so more users will attempt using the water-based coatings in the future.